1. Field of the Invention
This invention relates to a bio-sensing apparatus provided with a plurality of sensor sections, each of the sensor sections reflecting or transmitting light, whose physical characteristics vary for different kinds of samples. This invention particularly relates to a multi-channel bio-sensing apparatus capable of simultaneously performing measurements with respect to a plurality of samples with one time of sample setting.
2. Description of the Related Art
As bio-sensing apparatuses for use in analyses of biomolecules, there have heretofore been known bio-sensing apparatuses, wherein measuring light is irradiated to a sensor chip that reflects or transmits light, whose physical characteristics vary for different kinds of samples, and wherein physical characteristics of reflected light, which has been reflected from the sensor chip, or transmitted light, which has passed through the sensor chip, are detected. With the bio-sensing apparatuses, in cases where a measurement is performed in a state in which a known antigen (or a known antibody) has been bound to the sensor chip, a difference in physical characteristics of the reflected light or the transmitted light, which difference occurs in accordance with whether an antigen-antibody reaction has or has not occurred, is capable of being detected. In accordance with the results of the detection of the difference in physical characteristics of the reflected light or the transmitted light, it is possible to detect whether the antibody (or the antigen) is or is not contained in the sample. By way of example, certain kinds of the sensor chips utilize a phenomenon, in which the scattering or the absorption of light having a specific wavelength is enhanced by localized plasmon resonance, and the optical intensity of the light is thus attenuated.
For example, in order for the measurement efficiency to be enhanced, it is desired that the measurements with respect to a plurality of samples are capable of being performed with one time of sample setting. With the multi-channel sensing techniques described above, it is possible to perform analyses, wherein measurements with respect to the plurality of the samples are performed simultaneously, such that the basic conditions, such as the kind of a reference and the kind of the sample to be analyzed, are kept identical, and such that only a specific condition is altered, and wherein only the data obtained due to the difference in specific condition are analyzed.
A sensing apparatus has been proposed, wherein measuring light is irradiated collectively to a sensor chip, which is provided with a plurality of sensor sections (i.e., wells) located in an array form, and wherein physical characteristics of reflected light beams, which have been reflected from the sensor sections, are detected collectively by use of a detector provided with detecting devices located in an array form. The proposed sensing apparatus is disclosed in, for example, International Patent Publication No. WO/2004/113880.
With a multi-channel sensing operation, the measurements with respect to a plurality of samples may be performed simultaneously, such that the basic conditions are kept identical, and such that only the specific condition is altered. In such cases, in order for the data obtained due to the difference in specific condition are to be analyzed accurately, it is important that the measurement conditions do not vary markedly for different samples.
With the sensing apparatus disclosed in, for example, International Patent Publication No. WO/2004/113880, it is necessary for the measurements to be performed such that (a) the measuring light may be irradiated uniformly to all of the sensor sections on the sensor chip, such that (b) the position of each of the sensor sections and the position of the corresponding one of the detecting devices may be accurately matched with each other, and such that (c) the reflected light beam, which has been reflected from each of the sensor sections, may be detected so as to be free from adverse effects of (i.e., interference with) the reflected light beams, which have been reflected from the other sensor sections, through the setting of the pitches of the sensor sections at somewhat large pitches.
However, with the sensing apparatus disclosed in, for example, International Patent Publication No. WO/2004/113880, it is not always possible to satisfy all of the requirements described under (a), (b), and (c) appropriately, and therefore it is not always possible to perform accurate measurements. Also, as the number of the sensor sections becomes large, it will become more difficult to satisfy the requirements described under (a), (b), and (c). Therefore, limitation is imposed upon the number of sensing channels. Accordingly, under existing circumstances, a multi-channel bio-sensing technique for at least three channels has not yet been used in practice.